Screw and driver

ABSTRACT

A screw having a head and a reduced shank, and having a socket formed therein opening through the outer surface of the head, the socket having a larger portion disposed entirely within the head and being non-circular about the screw axis, and a smaller portion, also non-circular about the screw axis and extending into the shank portion of the screw, and a drive having a bit shaped at its extended end to engage snugly in both portions of the screw socket.

United States Patent 1w Parsons 1 June 10, 1975 l l SCREW AND DRIVER [76] lnventur: Joseph D. Parsons, Fl l W, Osage $1.. Plattshurg. Mo. 64477 22 Filed: Feb.8, I974 1211 Appl. No.1 440,850

Primary E.ruminer.lames L. Jones, Jr. Attorney. Agent, or FirmJ0hn A. Hamilton 57 I ABSTRACT 1 Claim, [0 Drawing Figures I52] U.S. Cl. 81/71; 85/45. l-tS/St) A [5|] int. Cl BZSb l3/48 {SKI Field of Search til/71. M5 50 A; 95/45 l56| References Cited UNl'lkD STATES PA'lEN'l'S 2.800819 7/l957 West v. i l45/SU A 3.293.978 I'l/IJhfi Handle H l45/5(l A 3.4612(l) 8/!969 l'odulskvuw 81/71 X FOREIGN PATENTS OR APPLICATIONS 6681\63 7/192) France i v v i i i i i v i it til/7i SCREW ANI) DRIVER This invention relates to new and useful improvements in screws and screwdrivers, and has as its principal object the provision of a screw having a recess engageable by a correspondingly configurated driver, the recess and driv er being so shaped as to provide a deeper, more secure engagement of the driver in the screw. whereby to provide greater turning power and less likelihood of slippage or accidental disengagement thereof.

Another object is the provision of a screw and driver combination wherein the driver socket of the screw extends completely through the screw head into the screw shank. whereby the deep engagement of the driver therein may be obtained without objectionable thickening of the screw head.

A further object is the provision of a screw and driver combination of the character described wherein the portion of the driver socket extending into the screw shank is of reduced dimensions. laterally of the screw axis, so that the increased depth ofengagement may be obtained without objcctionably weakening the screw at the juncture of the head and shank portions thereof.

A still further object is the provision of a screw and driver combination of the character described having pilot means for assisting the insertion of the driver into the socket.

Other objects are simplicity and economy of structure. efficiency and dependability of operation, and ease and economy of manufacture.

With these objects in view. as well as other objects which will appear in the course of the specification, ref erence will be had to the accompanying drawing, wherein;

FIG. 1 is a side elcvational view of a screw driver constructed in accordance with one form of the present invention.

FIG. 2 is an enlarged end view of the driver shown in FIG. 1,

FIG. 3 is an enlarged. fragmentary side elevational view of the driver shown in FIG. I, shown in operative engagement with a screw constructed according to the present invention, said screw being shown fragmentarily and partially in section,

FIG. 4 is an outer face view of the head of the screw shown in FIG. 3,

FIG. 5 is a view similar to FIG. 2, showing a modified form of the driver,

FIG. 6 is a view similar to FIG. 3, showing the driver of FIG. 5 engaged in a corresponding screw,

FIG. 7 is an outer face view of the head of the screw shown in FIG. 6,

FIG. 8 is a view similar to FIG. 2, showing a driver of another modified form.

FIG. 9 is a view similar to FIG. 3. showing the driver of FIG. 8 engaged in a corresponding screw, and

FIG. I0 is an outer face view of the head of the screw shown in FIG 9.

Like reference numerals apply to similar parts throughout the several views, and in FIGS. 1-3, the numeral 2 applies generally to a screw driver consisting of a straight. elongated shank 4, having a handle 6 affixed to one end thereof. and a screw-engaging bit indicated generally by the numeral 8 at its opposite end, said bit being formed by specially conligurating that end of the shank. In FIGS. I-3. said bit includes a first portion I0 directly adjacent the driver shank and of square crosssectional contour coaxially with the shank. a reduced second portion 12 extending coaxially from section 10, being of the same general cross-sectional contour as section 10 but of reduced dimensions, and of greater axial length than section 10, and a pilot portion I4 forming an axial extension of section I2, being of the same cross-sectional shape as sections 10 and 12 but tapering to a point. While all of the bit sections are shown as having a square cross-sectional contour, it will be understood that this shape may take any non circular form, such as hexagonal, triangular, oval or the like.

The screw provided for use with the driver of FIGS. 1-3 is shown in FIGS. 3 and 4, and is indicated generally by the numeral 16. It includes the usual enlarged head 18 and a reduced. integral threaded shank 20 extending from said head. To receive the bit 8 of the driver. the screw is provided with a socket indicated generally by the numeral 22 and opening through the outer surface of screw head 18. concentrically with shank 20. Said socket includes an outer section 24 which is square and sized to receive bit section 10 slidably but non-rotatably therein, an intermediate section 26 sized to receive bit section 12 slidably but nonrotatably therein. and an inner section 28 sized to receive bit pilot section I4 snugly therein. Socket section 24 is disposed entirely within screw head 18 and is of substantially less depth than the thickness of said head, while socket section 26 may extend to any desired dis tance into screw shank 20, but is of sufficiently smaller cross-sectional area than said shank as not to objectionably weaken said shank against torsional stress, particularly at the juncture of said shank with head 18.

In operation, the screw of course is turned by inserting bit I8 into socket 22, and applying torque to said bit by means of handle 6. The primary advantage of the bit-socket configuration shown and described is that it provides a very deep, secure engagement of the bit in the screw which is extremely unlikely to allow accidental disengagement. and which allows for the application of a far greater torque than ordinary screwdrivers with no danger of deforming or malforming the parts. The allowability of greater torque is provided by the long axial length of the bit, it being apparent that the longer the bit the greater the torque it can apply without deforming the parts, since the load is thereby distributed over a greater axial length of the screw, and the load per unit length is accordingly decreased. The greater length of the bit, and corresponding depth of the socket, is made possible by the special configuration thereof shown, the reduction of cross-sectional dimensions of socket section 26 and bit section I2 permitting them to extend into the screw shank as shown. This provides a sort ofdouble-grip" action, or even triplegrip, since all three sections of the bit will apply a rotative torque in the corresponding sections of the socket. Socket section 24, disposed entirely within the head. may have transverse dimensions as great as permitted by the dimensions of the head itself. lts transverse dimensions prefcrably should be as large as practically possible, since it provides the major portion of the rotative torque, its corners" having the greatest moment arm relative to the screw axis. In many cases. its transverse dimensions may be substantially greater than those of the screw shank. The axial depth of socket section 24 should also be as great as possible. subject to the limitation that it should not extend so close to the base of the head as to objectionably weaken the screw metal at the juncture of the head and shank. Thus the depth of socket section 24 must be substantially less than the thickness of the head. Socket section 26, however, may be of any desired depth, being reduced in transverse dimensions to a sufficient degree that it does not objectionably weaken the screw, either at the juncture of the head and shank, or in the remaining wall of the shank in spaced relation from the head.

If bit section 12 is axially longer than section 10, as shown and described, section 12 acts as a pilot for guiding section 10 into socket section 24, since bit section 12 is confined in socket section 26 as bit section 10 enters socket section 24. Section 14 of the bit pilots section 12 thereof into socket section 26.

FIGS. -7 show a slight modification of structure. In this form of the invention, the bit and socket configurations are generally similar to those shown in FIGS. 1-4, corresponding parts bearing corresponding numerals. In this species, the bit 8 is provided with a square or otherwise non-circular first section 30 corresponding to section of FIGS. 1-4, and screw socket 22 has a section 32 corresponding to section 24 of FIGS. 1-4. However. the second or reduced section 34 of the bit in FIGS. S-7 constitutes a thin, relatively broad blade the plane of which lies in the bit axis, and socket 22 is provided with a corresponding section 36 for receiving said blade. The axial length of blade 34 is greater than that of section 30, whereby to serve as a pilot for guiding bit section 30 into socket section 32, and the corners of the extended end of the blade are cut off diagonally, as indicated at 38, whereby said blade is piloted into socket section 36. The operation of this species is also generally identical to that of FIGS. 1-4. However, while somewhat more difficult to form than the species of FIGS. 1-4, it has the advantage that the longitudinal edges of blade 34 may be extended somewhat closer to the outer surface of screw shank 20, so that its edges have a greater moment arm relative to the screw shank, with the result that a greater torque can be exerted by said blade than can be exerted by section 12 of the bit in FIGS. 1-4. The blade can be extended closer to the screw shank surface because, since the socket section 36 required to receive the blade is relatively thin, it leaves a greater portion of the cross-sectional area of the shank solid and undisturbed.

FIGS. 8-10 show another modification of structure, having the advantages of extreme simplicity and economy of manufacture, in which the driver bit 8 is simply a flat blade 40 having a narrowed extension section 42, rounded at its extreme end as indicated at 44, while screw socket 22 comprises a slot 46 formed diametrically in the outer surface of the screw head, but being of substantially lesser depth than the screw head, and a section 48 extending from the base of slot 46 and extending into the screw shank. Section 48 is of course sized to receive bit section 42 slidably therein. Bit section 42 is axially longer than the depth of slot 46, whereby to pilot blade 40 into said slot, while the rounded end 44 of bit section 42 pilots it into socket section 48. The operation of this species of the invention corresponds to that of the other species shown.

While I have shown and described certain specific embodiments of my invention, it will be readily apparent that many other minor changes of structure and operation could be made without departing from the spirit of the invention.

What I claim as new and desire to protect by Letters Patent is:

1. A screw and screw driver combination comprising: a7 a screw having a head and a reduced shank extending from said head, said screw having a socket formed therein and opening through the surface thereof opposite from said shank, said socket having a first section disposed entirely within said head and being square about the screw axis, a second section extending inwardly from the inner end of said first section and into said shank. said second section being coaxial with said first section and also square about the screw axis but of reduced size, and being of greater axial length than said first section, and a third section at the inner end of said second section, said third section forming an axial extension of the square cross-sectional contour of said second section but tapering to a point toward the free end of said shank, so as to be pyramidal in form, and b. a screw driver having a bit corresponding in shape to the internal contour of said socket and adapted to be inserted slidably but non-rotatably therein to fill said socket completely, and having first, second and third sections corresponding respectively to the first, second and third sections of said socket, whereby as said bit is inserted into said socket. said third bit section first engages in the outer end of said second socket section both to center said bit coaxially with said socket, and also, if the bit is angularly misaligned with said socket, to apply a rotary cam torque to said bit to turn it into angular registry with said socket, so as to facilitate the entry of the first and second bit sections into the corresponding sections of said socket. 

1. A screw and screw driver combination comprising: a. a screw having a head and a reduced shank extending from said head, said screw having a socket formed therein and opening through the surface thereof opposite from said shank, said socket having a first section disposed entirely within said head and being square about the screw axis, a second section extending inwardly from the inner end of said first section and into said shank, said second section being coaxial with said first section and also square about the screw axis but of reduced size, and being of greater axial length than said first section, and a third secTion at the inner end of said second section, said third section forming an axial extension of the square cross-sectional contour of said second section but tapering to a point toward the free end of said shank, so as to be pyramidal in form, and b. a screw driver having a bit corresponding in shape to the internal contour of said socket and adapted to be inserted slidably but non-rotatably therein to fill said socket completely, and having first, second and third sections corresponding respectively to the first, second and third sections of said socket, whereby as said bit is inserted into said socket, said third bit section first engages in the outer end of said second socket section both to center said bit coaxially with said socket, and also, if the bit is angularly misaligned with said socket, to apply a rotary cam torque to said bit to turn it into angular registry with said socket, so as to facilitate the entry of the first and second bit sections into the corresponding sections of said socket. 